The awards are a bellwether for the Oscars in March, and are being closely watched this year as they come with Hollywood engulfed in the worst sexual misconduct scandal in its history.

Allegations from harassment to rape have sparked the downfall of numerous powerful industry players, starting with movie mogul Harvey Weinstein and including actors Kevin Spacey, Jeffrey Tambor and Louis C.K. as well as filmmaker Brett Ratner.

In the aftermath of Saturday's second "Women's March" which brought together hundreds of thousands of people in the United States -- between 300,000 and 600,000 in Los Angeles alone -- all SAG statuettes were being presented by actresses, including Halle Berry, Dakota Fanning, Lupita Nyong'o and Emma Stone.

The actors guild has been keen to back the Time's Up movement created by 300 influential women in Hollywood to fund the defence of victims of sexual abuse, as well as the #MeToo movement against sexual misconduct.

Unlike at the Golden Globes, where all actresses dressed in black, sequins, sparkles, feathers and an air of Tinseltown glam were back on the SAG red carpet.

"We are living in a watershed moment and we march forward with active momentum and open ears, let's make sure we are leading the charge with empathy and diligence, because fear and anger never win the race," said Bell as she opened the show.

William H. Macy picked up the first award of the night -- best actor in a comedy series -- while Julia Louis-Dreyfus, who is battling cancer and couldn't attend, won the female equivalent.

"I think it's a glorious way to make living, especially in this day and age, when so many people can't recognise the truth or don't think it's important," said Macy.

HBO's "Veep," starring Louis-Dreyfus as hapless former president Selina Meyer, won best ensemble in a comedy series.

"Four Billboards" took four nods in three categories -- best ensemble cast, best lead actress (Frances McDormand), and best supporting actor (Woody Harrelson and Sam Rockwell).

On the TV side, three series were tied at the top with four nominations each: HBO drama "Big Little Lies" and -- including the stunt team nominations -- Netflix sci-fi thriller "Stranger Things" and wrestling comedy "Glow."

SAG nominations are the second major announcement in Tinseltown's glittering awards season, which climaxes with the Academy Awards in March.

Guillermo del Toro's acclaimed 1960s-set fantasy romance "The Shape of Water" led the Golden Globe nominations with seven but picked up just two SAG nods.

"Three Billboards," starring McDormand as a mother seeking to avenge the rape and murder of her daughter, picked up six Globes nods and has been seen as a top Oscars contender since taking the influential audience award at the Toronto International Film Festival in September.

While far less flashy than the Globes, the SAG awards are seen as more of an indicator of Oscars glory.

Members represent about 1,200 of the roughly 6,000 voters for the Academy of Motion Picture Arts and Sciences.